Time delay device for automatic switches



Nov. 19, 1935. M. P. WHITNEY 2,021,822

TIME DELAY DEVICE FOR AUTOMATIC SWITCHES Filed April 12, 1930 3Sheets-Sheet l lNVENTOR Maurice P. Whi tn c ATTORNEY Nov. 19, 1935. p wrr 2,021,822

TIME DELAY DEVICE FOR AUTOMATIC SWITCHES Filed April 12, 1930 3Sheets-Sheet 2 31 a 1 30 13 j 00 E 99 Q. 1 39 2g $$$$$$$$i 8.;.u.......-nna

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TTORNEY NOV. 19, 1935. M, p w E 2,021,822

TIME DELAY DEVICE FOR AUTOMATIC SWITCHES Filed April 12, 1930 3SheetsSheet 3 To IGNITION 4 ynmwnw /5.2 Fig.

INVENTOR Maurice R Wh 'Liney A TTORNE V Patented Nov. 19, 1935 TIltiEDELAY DEVICE FOR AUTOMATIC SWITCHES Maurice P. Whitney, Elmira, N. Y.,assignor to Eclipse Machine Company, Elmira, N. Y., a corporation of NewYork Application April 12, 1930, Serial No. 443,833

4Ciaims.

This invention relates to a novel time delay device for an automaticswitch and particularly to a means for delaying the closing of anautomatic switch for starting mechanism.

One object of the device is the provision of a novel time delay forautomatic switches which is reliable and efficient and generallysuperior to those heretofore known.

Another object is to provide such a time delay which is adapted to delaythe closing of the switch but which provides for a quick substantiallyunimpeded opening thereof.

A further object of the invention is the provision of such a deviceembodying a dash pot for the timing element.

Another object is to provide such a device embodying a dash pot which islocated within the body of the switch, thus rendering the device compactand well protected from accidental inury.

A further object is to provide such a device which is readily adjustableto regulate the timing thereof and which accurately maintains suchadjustment.

A further object of the invention is the provision of such a devicewhich is economical to manufacture, is easily assembled and requires butfew parts to be added to the switch assembly.

Other objects and advantages of the invention will become apparent fromthe following description taken in connection with the accompanyingdrawings in which:-

Fig. 1 is an elevation of an automatic switch parts being in axialsection;

Fig. 2 is an enlarged expanded view in perspective oi certain of theparts;

Fig. 3 is an enlarged detail in section of certain parts of the switchshown in normal posiion;

Fig. 4 is a similar view showing the parts in operative position;

Fig. 5 is a similar view showing the parts in their position at theinstant the switch has been opened; and

Fig. 6 is a schematic view of an automatic starting device embodying theimproved automatic switch, incorporating the novel time delay element. I

Referring first to Fig. 1 of the drawings, the switch 9 comprises acasing III of any convenient form having a switch controlling solenoid Iand a contact controlling solenoid l2 rigidly mounted therein. SolenoidH is adapted to control the position of a switch member l3 which when inits closed position bridges a pair of contacts l4 and IE to complete astarting motor circuit. One end of the coil I6 of solenoid H isconnected to a binding post ll while the opposite end of said coil isconnected to a bracket l8 mounted rigidly er 2| of solenoid I,electrically insulated there from, and is yieldably held against ashoulder 22 thereon as by means of a spring 23. Spring 23 15 is held inposition and connected to plunger 2| by suitable means such as a dishedWasher 23 riveted on the end of plunger 2| and forming a seat for theouter end of said spring. Plunger 2|, is formed in two parts 2| and 2|which fit 20 loosely within a cylindrical core 29 of solenoid Parts 2|and 2| are fixed together in any suitable way as by means of a threadedconnection 24. Part 2| is provided as best shown in Fig. 2 with portions25 and 26 of progressively reduced diameters forming shoulders 21 and 28respectively and cooperating with the end of part 2| I to form annularchambers or spaces within the cylinder 29. Part 2 I is also providedwith a longitudinal slot 30 extending throughout its length.

A cup valve of any suitable material is loosely mounted in the spacebetween members 2 and 21 with its inturned portion 32 adapted to restagainst shoulder 28 and its cylindrical portion adapted to surround theportion 25 of member 35 2|. Valve 3| has a working 'fit within cylinder29, and may if desired be provided with an expander 3 therein to ensurean air-tight fit.

It will be noted that the space between the shoulder 2801 member 2 l andshoulder 33 formed by the end of 2| is considerably greater than thethickness of the inturned portion 32 of the cup valve 3| and of expander3|, so that the cup valve is mounted on the plunger 2| with considerablelongitudinal lost motion. When cup valve 3| rests against shoulder 33 itforms with such shoulder an obturator preventing the escape of air pastthe member 2|, but when the valve rests against the shoulder 28 air canreadily pass through the space between shoulder 33 and inturned portion32 and traverse the longitudinal slot 30.

The end oi cylinder 29 opposite that through which plunger 2| protrudesis closed by suitable means such as a plug 34 threaded within casing Illand having a tight fit within said cylinder. Plug 34 may be providedwith an adjustable bleeder which as illustrated comprises a channel 35axially traversing the same, and a radial open ing 36 intersecting saidchannel. A plug 31 of suitable compressible material such as rubber orfibre is pressed against the opening of channel 35 as by means ofthreaded plug 38, the pressure being regulated by adjusting the plug tovary the rate of flow of air through said channel.

Plunger 2| is normally maintained in the position illustrated in Figs. 1and 3 by means such as a spring 39 hearing against a partition member 40of casing in at one end and against a collar 4! fixed on the plunger 2|at its other end. The length of the stroke of plunger 2i may beregulated by means such as the adjustable stop 42 mounted in casing Illand forming an abutment for said plunger.

In Fig. 6 of the drawings one form of electrical connections is shownwhereby the automatic switch may be used in an automatic starting devicefor internal combustion engines. A battery 50, engine driven generatorG, automatic cut-out 5i and ammeter A are connected as shown or in anyusual or preferred manner so that the generator will charge the batterywhile the engine is running. A starter of the automatic mesh typeindicated generally at 52 is adapted to be energized by said battery,and switch 3 is designed to automatically control the actuation thereofwhenever the ignition switch 53 is closed by the operator.

For this purpose, a cable 54 is arranged to connect the ungrounded endof battery 50 to contact M of switch 9. Contact i5 is connected througha single turn solenoid 55 to cable 55 leading to the starter 52. Switchcontrolling solenoid l I is connected to the ignition circuit by a lead51 so that closure of the ignition switch 53 will energize said solenoidif contacts l9, l8 are closed. A voltage coil 58 forming a part ofsolenoid i2 is connected to the starter circuit at 59 and to the groundat 60, and a generator coil 5| is connected to the generator circuit at52 and is also grounded at 60.

In operation, when the ignition switch 53 is closed, solenoid I I drawsplunger 2i down, closing switch i3, i4, I 5 and causing the energizationof the starter. Series coil 55 and voltage coil 58 are alsosimultaneously energized and exert opposing forces on contact plungerl9, coil 55 acting to hold the contact closed, and coil 53 tending toopen the contact. As long as the starter is cranking the engine thecurrent in the starter circuit is so heavy that coil 55 is stronger thancoil 58, and contact I! is held closed. When the engine starts, however,the load on the starting motor is relieved and the starting current isreduced so that coil 53 overcomes coil 55 and withdraws contact plungeri9 from contact bracket l3, opening the circuit through switch solenoidH and releasing switch member i3. The battery connection to the starteris thus broken, but since voltage coil 58 is still connected to themotor, the contact l9 will be held open by the slight current generatedby the spinning of the motor armature in its residual field. Before thestarting motor has stopped, the generator coil H has become sufficientlyenergized by the generator G to retain the contact l9 open as long asthe engine is running.

If the engine should stall for any reason, the generator coil 5i becomesdeenergized, allowing contact I9 to close and the operation is repeatedas long as the ignition switch remains closed.

The time delay device which forms the subject matter of the presentinvention is provided in order to allow the engine to come completely torest before the switch l3, l4, I5 is allowed to close. This time delayis furnished by the dash pot action of the valve 3| in cylinder 23 sinceduring the inward stroke of plunger 2| valve 3! rests against theshoulder 33 and forms there- 10 with a tight piston. The time delay maybe regulated either by adjusting the plug 33 to vary the rate of escapeof air through the channel 35 or by varying the stroke of plunger 2| bymeans of the adjustable stop l2. 16

Since large amounts of current are carried in the starting circuit, itis obvious that contacts I 3, l4, and I5 will be subject to heavy arcingif the break of said contacts is not instantaneous. With this purpose inview, the valve 3i is given 20 the lost motion referred to with respectto plunger 2|, so that return movement of plunger 2| is unimpeded by thefriction of said valve in the cylinder 29.

This operation is best illustrated in Figs. 4 and 25 5 of the drawings.Fig. 4 illustrates the position of the parts when the switch is closed.It will be noted that valve 3! rests against shoulder 33 and spring 23is slightly compressed in holding switch member i3 against contacts Iand I5. 30 When the circuit through coil I 6 is broken by the controlsolenoid i2, (Fig. 1) spring 39 immediately expands and moves plunger 2ioutwardly to the position shown in Fig. 5. As there illustrated, it willbe seen that a clean break of the contacts is obtained by the time thelost motion between valve 3| and plunger 2! has been taken up.

Although but one embodiment of the invention has been illustrated anddescribed in detail, it will be understood that this structure is notexclusive and further embodiments will now suggest themselves to thoseskilled in the art and certain parts may be combined, altered or omittedand changes made in the arrangement and mode of operation thereofwithout departing from the spirit of the invention.

Reference will therefore be had to the claims hereto appended for adefinition of the scope of the invention.

What is claimed is:--

1. An automatic electric switch including a fixed pole piece, a movablearmature cooperating therewith, a contact element, a yielding connectionbetween the armature and contact'which is loaded when the switch isclosed and permits the armature to engage the 'pole piece to close themagnetic circuit therethrough, means for retarding the switch closingmotion of the armature, said retarding means having a lost motionconnection with said armature to allow an unimpeded initial switchopening movement thereof to unload the yielding connection and breakaway said contact.

2. An automatic electric switch including a fixed pole piece, a movablearmature cooperating therewith, a contact element, a yielding connectionbetween the armature and contact which is loaded when the switch isclosed and permits the 70 armature to engage the pole piece to close themagnetic circuit therethrough, means for retarding the switch closingmotion of the armature, said retarding means having a lost motionconnection with said armature to allow an unimpeded initial switchopening movement thereo! to unload the yielding connection and breakaway said contact, said armature having an abutment adapted to engagethe contact element to break open the switch during the lost motion ofthe armature with respect to the retarding means.

3. A magnetic switch for automatic starting mechanism including fixedand movable contacts, operating means for the movable contact includinga yielding connection for maintaining the engagement of the contacts,retarding means for said operating means, and means for rendering theretarding means inoperative tor a portion of the stroke of the operatingmeans greater than that which loads the yielding connection.

4. A magnetic switch for automatic starting mechanism including fixedand movable contacts, operating means for the movable contact includ--ing a magnetic plunger and a spring loaded by final closing movement ofthe plunger for hold-v ing the contacts closed, and retarding means forthe plunger having a lost motion connection thereto which allows asuflicient'free movement 10 of the plunger to unload said spring andbreak, said contacts.

MAURICE P. WHITNEY

